1. Field of Use
The present invention pertains generally to high speed drills or the like which operate, for example, in the neighborhood of 50,000 RPM. The drills or other tools usable with these high speed spindles must be quickly, easily, and often frequently removed and/or replaced.
2. Description of the Prior Art
Examples of prior art tools with which the present invention find utility, are shown in my U.S. Pat. Nos. 3,840,767 of Oct. 8, 1974; 3,807,815 of Apr. 30, 1974; and 3,794,335 of Feb. 26, 1974, all of which are owned by the assignee of the present application.
Certain other prior art devices of this general character have used centrifically-operated driving connections between the tool holder and the spindle, but their use has been somewhat unsatisfactory because of slipping of the tool when excessive resistance was build up to the tool during the drilling operation, and consequently, a positive rotation of the tool could not be assured. Furthermore, some of these prior art devices had no provision for ensuring that the tool holder remain in the spindle when the rotational forces on the tool were reversed or when the spindle is operating at low or no speed.
Examples of some prior art tools of this general type are shown in Kosmowski U.S. Pat. Nos. 3,795,455 of Mar. 5, 1974; 3,687,467 of Aug. 29, 1972; and 3,672,256 of June 27, 1972.